Mitsubishi Electric 800 Series Instruction Manual page 416

5.11.7 PID gain tuning
Changing the PID control manipulated amount and measuring the PID control response enable automatic setting of the
constant optimal for PID control.
For tuning, use the step response method or the limit cycle method.
Pr. Name
1211 PID gain tuning timeout time 100 s
A690
1212 Step manipulated amount
A691
1213 Step response sampling
A692 cycle
1214 Timeout time after the
A693 maximum slope
1215 Limit cycle output upper
A694 limit
1216 Limit cycle output lower limit 1000%
A695
1217 Limit cycle hysteresis
A696
1218 PID gain tuning setting
A697
1219 PID gain tuning start/status
A698
 Step response method
• In the step response method, the manipulated amount is changed step by step for the real system. From the change in the
measured values, the maximum slope (R) and the equivalent waste time (L) are calculated to determine each constant.
Manipulated
amount[%]
Measured value[%]
Equivalent
waste time L (s)
PID gain tuning start
• The step manipulated amount (Pr.1212 - 1000) is added to the present manipulated amount.
• The measured value is taken for every sampling cycle of step response (Pr.1213). From the variation between the
measured values (Y) and the time (t), the maximum slope (R) is calculated.
Initial Setting range
value
1 to 9999 s
1000% 900 to 1100%
1 s 0.01 to 600 s
10 s 1 to 9999 s
1100% 900 to 1100%
900 to 1100%
1% 0.1 to 10%
0 0, 100 to 102, 111, 112,
121, 122, 200 to 202,
211, 212, 221, 222
0 0
1
2
8
9, 90 to 96
Maximum Maximum Maximum
slope R slope R slope R
(R=Y/T) (R=Y/T) (R=Y/T)
STF
PID
PGT
Description
Set the time after the PID gain tuning starts until a
timeout error occurs.
Set the step manipulated amount when using the step
response method to perform the PID gain tuning.
Set the cycle for sampling of measurement values when
using the step response method to perform the PID gain
tuning.
Set the time after the measurement of the maximum
slope until the completion of the tuning when using the
step response method to perform the PID gain tuning.
Set the upper limit value of the two-position output when
using the limit cycle method to perform the PID gain
tuning.
Set the lower limit value of the two-position output when
using the limit cycle method to perform the PID gain
tuning.
Set the hysteresis of the set point when using the limit
cycle method to perform the PID gain tuning.
Select the target loop, method, and control adjustment
method for the PID gain tuning.
PID gain tuning function disabled
PID gain tuning start
During PID gain tuning (read only)
PID gain tuning forced end
Tuning error (read only)
Step manipulated amount
(Pr.1212-1000)
PID gain tuning end
Measured value
variation range Y
Equivalent time constant T (s)
Timeout time after the maximum slope (s)
(Pr.1214)
5.11 (A) Application parameters
Time
Time
415
5. PARAMETERS
3
4
5
5
5
6
7
8
9
10